Introduction to optical fiber biosensors

Tosi, Daniele; Sypabekova, Marzhan; Bekmurzayeva, Aliya; Molardi, Carlo; Dukenbayev, Kanat

doi:10.1016/b978-0-12-819467-6.00001-9

Cited by 2 publications

(1 citation statement)

References 39 publications

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“…The distal ends of the optical fibres were cleaved and rinsed with pure ethanol. The freshly cleaved distal ends were immersed in 6M NaOH for 1 h to activate the hydroxyl groups at the optical fibre tip for covalent bonding [52][53][54], which was conducted in a sealed environment. Afterwards, the optical fibres were rinsed thoroughly with MilliQ water and left to dry at room temperature.…”

Section: Surface Functionalisation and Coating Of The Optical Fibresmentioning

confidence: 99%

Surface Functionalised Optical Fibre for Detection of Hydrogen Sulphide

Baghapour,

Nehema,

Zhang

et al. 2023

Biosensors

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Dysregulated production of hydrogen sulphide in the human body has been associated with various diseases including cancer, underlining the importance of accurate detection of this molecule. Here, we report the detection of hydrogen sulphide using fluorescence-emission enhancement of two 1,8-naphthalimide fluorescent probes with an azide moiety in position 4. One probe, serving as a control, featured a methoxyethyl moiety through the imide to evaluate its effectiveness for hydrogen sulphide detection, while the other probe was modified with (3-aminopropyl)triethoxysilane (APTES) to enable direct covalent attachment to an optical fibre tip. We coated the optical fibre tip relatively homogeneously with the APTES-azide fluorophore, as confirmed via x-ray photoelectron spectroscopy (XPS). The absorption and fluorescence responses of the control fluorophore free in PBS were analysed using UV-Vis and fluorescence spectrophotometry, while the fluorescence emission of the APTES-azide fluorophore-coated optical fibres was examined using a simple, low-cost optical fibre-based setup. Both fluorescent probes exhibited a significant increase (more than double the initial value) in fluorescence emission upon the addition of HS− when excited with 405 nm. However, the fluorescence enhancement of the coated optical fibres demonstrated a much faster response time of 2 min (time for the fluorescence intensity to reach 90% of its maximum value) compared to the control fluorophore in solution (30 min). Additionally, the temporal evolution of fluorescence intensity of the fluorophore coated on the optical fibre was studied at two pH values (7.4 and 6.4), demonstrating a reasonable overlap and confirming the compound pH insensitivity within this range. The promising results from this study indicate the potential for developing an optical fibre-based sensing system for HS− detection using the synthesised fluorophore, which could have significant applications in health monitoring and disease detection.

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Section: Surface Functionalisation and Coating Of The Optical Fibresmentioning

confidence: 99%

Surface Functionalised Optical Fibre for Detection of Hydrogen Sulphide

Baghapour,

Nehema,

Zhang

et al. 2023

Biosensors

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Surface Modification of Polystyrene with Boronic Acid for Immunoaffinity-Based Cell Enrichment

Shirani,

Razmjou,

Asadnia

et al. 2024

Langmuir

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Obtaining an enriched and phenotypically pure cell population from heterogeneous cell mixtures is important for diagnostics and biosensing. Existing techniques such as fluorescentactivated cell sorting (FACS) and magnetic-activated cell sorting (MACS) require preincubation with antibodies (Ab) and specialized equipment. Cell immunopanning removes the need for preincubation and can be done with no specialized equipment. The majority of the available antibody-mediated analyte capture techniques require a modification to the Abs for binding. In this work, no antibody modification is used because we take advantage of the carbohydrate chain in the Fc region of Ab. We use boronic acid as a cross-linker to bind the Ab to a modified surface. The process allows for functional orientation and cleavable binding of the Ab. In this study, we created an immunoaffinity matrix on polystyrene (PS), an inexpensive and ubiquitous plastic. We observed a 37% increase in Ab binding compared with that of a passive adsorption approach. The method also displayed a more consistent antibody binding with 17 times less variation in Ab loading among replicates than did the passive adsorption approach. Surface topography analysis revealed that a dextran coating reduced nonspecific antibody binding. Elemental analysis (XPS) was used to characterize the surface at different stages and showed that APBA molecules can bind upside-down on the surface. While upside-down antibodies likely remain functional, their elution behavior might differ from those bound in the desired way. Cell capture experiments show that the new surface has 43% better selectivity and 2.4-fold higher capture efficiency compared to a control surface of passively adsorbed Abs. This specific surface chemistry modification will allow the targeted capture of cells or analytes with the option of chemical detachment for further research and characterization.

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Introduction to optical fiber biosensors

Cited by 2 publications

References 39 publications

Surface Functionalised Optical Fibre for Detection of Hydrogen Sulphide

Surface Functionalised Optical Fibre for Detection of Hydrogen Sulphide

Surface Modification of Polystyrene with Boronic Acid for Immunoaffinity-Based Cell Enrichment

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